a) Field of the Invention
This present concept relates to an electric hand tool, particularly portable electric screwdrivers. In general, portable electric screwdrivers come in two general categories. The first category is specifically designed to replicate or act more as a portable electric hand drill. These hand drills are configured in the general shape of a handgun having a lower handle section running essentially vertically, with a transverse body section where the motor is housed in the drive shaft which turns the spindle. The spindle head has a chuck which holds either the drill bit or the screwdriver bit. Generally, the power source is contained within the handle portion and provides for enough space to store a large battery with significant amounts of power to run the drill for long periods of time. The spindle chuck is generally fixed in one direction or location offering limited range of movement.
The second category of portable electric screwdriver is one that is generally designed to replicate a handheld screwdriver. The housing on these portable handheld devices is generally cylindrical and has a power source in the handle section which is limited in size to the housing thus providing for a small battery with less amount of power to run for a limited period of time. The motor is also contained within the housing and drives a drive shaft which is connected to the screwdriver bit spindle section. In either case, users commonly encounter situations where they need to access small spaces such as car doors, home appliances and the like, where the use of a portable electric hand screwdriver with a spindle head which can pivot throughout a large range of angular positions within the small space, would be very beneficial to completing their respective tasks.
The following patents disclose a wide range of electrically powered hand tools.
b) Background Art
U.S. Pat. No. 1,970,369 discloses a coal drilling apparatus in Col. 1 line 33, a truck frame is mounted to an axel system and these are fitted with wheels that are adapted to rest upon and travel on rails. Further down at line 40, the mechanism has an electric motor connectable to a gearing with a chain and axles which actually change. The drilling mechanism is mounted upon a turntable carried by the truck frame. On the turntable is a motor which actuates the drilling mechanism. The motor is electric. A shaft is connected to the motor through the spur gears and the shaft has an arm with a locking member adapted to engage suitable apertures within the annular flange of the rim of the frame. By locking the member, the arm may be held in a preferred position of angular adjustment about the shaft.
U.S. Pat. No. 2,414,637 discloses a universal drill support. This device relates to machine or hand tools and a drill adapted for universal movement. The tool is adapted for universal swivel movement and a full 360° in 2 directions at right angles to each other. Referring to Col. 1 at line 27, a universal drill has an elongated handle member with a bore extending the length of the handle. The bore receives the bearing for a shaft on which a thrust collar is positioned and secured by a pin.
U.S. Pat. No. 5,533,581, discloses an electric hand tool, in particular a drill with a housing, an electric motor, a motor shaft parallel to the housing axis, a work spindle driven by the electric motor, work spindle driven by transmission gearing, the housing divided along a dividing plane for the purpose of switching from straight drilling to angular drilling. The drill spindle as referred to in Col. 4 at line 3 is rototably supported in a bearing of the housing and projects out of the housing. The drill spindle carries a drill chuck at its free and protecting out the housing for clamping a drill bit. Housing is divided along a dividing plane, into a front housing part for the drill spindle and a rear housing part containing the motor and the motor shaft. The dividing plane is situated at an angle of 45° relative to the axis of the motor shaft. The transmission gearing further down in Col. 4 at line 33, between the motor shaft and the spindle extends parallel to the motor shaft, but offset relative to the motor shaft.
U.S. Pat. No. 6,796,385 discloses a fastener driving machine and associated method. The machine is advantageously structured to provide a substantially constant level of torque to a delivery point on the head of the machine independent of the position of the head with respect to the driver. The machine is referred to in Col. 2 outline 57, has a driver structured to provide a given level of torque and also includes a transmission apparatus. The transmission has a gear mechanism, a support, an index, a head, and a structure to transmit the mechanical effort between the driver and the head. The index apparatus that is a first portion in the second portion with the first and second portions biased towards one another. With regard to adjusting the head to various conditions and configurations, referring to Col. 11 outline 17, to adjust the head and therefore move the delivery point in one position to another the lock rings unthreaded from the first teeth. The indexing housing and support are pulled apart to disengage the first and second teeth and the indexing housing is rotated with respect to the support until the desired position is achieved.
U.S. Pat. No. 2,348,266 discloses an angle tool holder for angle drills. An attachment is provided which can be easily connected to the usual spindle or chuck of a cutting or drilling machine, for instance the chuck of a portable drill. In Col. 2 at line 6, the casing has two complementary hollow sections. There is an upper hollow section and a lower hollow section, which face each other and are arranged around a vertically aligned bolt. Thus the upper or lower sections can be adjusted relative to one another in the radial direction around the bolt, the bolt being tightened and loosened to allow fixation or adjustment of the sections. Further, at line 53 Col. 2, the upper section has a shank extending outward so the ringed right angle from the bolts. The end of the upper shank extends outside of the shank and can be engaged with the spindle or tool holder. The end of the lower shank extends outside of the lower casing and can hold the tool. Rotation is provided from the upper shank through a gear transmission and into the transmission arranged around the vertical bolt. The rotation is then transmitted into a gear transmission which is connected to the lower shank. When the upper shank is rotated, and referring to Col. 3 at line 19, transmits rotation through the double gears of the transmission to the lower shank and rotates to the tool bit.
U.S. Pat. No. 5,372,420 discloses a device having a rotatable head with a housing having a first and second housing member. First housing member is rotatable relative to the second housing member between the first and second operating positions. The longitudinal axis of the first housing member is disposed substantially 90° relative to the longitudinal axis of the second housing member when in the first operating position. The longitudinal axis of first housing member is disposed coaxial with the longitudinal axis the second housing member when in the second operating position. A locking arm engages in the first housing member for retaining the member in the desired positions.
U.S. Pat. No. 6,168,287 discloses a combination of an electric power tool and an illuminating device received in the tool. Power tool has a handle for receiving batteries and a barrel with a drive shaft rotatably connected to the end of the barrel portion. The drive shaft is controlled by a switch which is electronically connected to the batteries of the drive shaft. An illuminating device includes two light bulbs attached to the drive shaft and being electronically connected to the switch so that by turning on the switch the bulbs illuminate. Further in Col. 2 at line 11, the electric power tool has a handle, a barrel, batteries within the barrel, with a cap on the lower end of the barrel to contain the batteries, a drive shaft from the barrel portion, a switch connected to the barrel portion, the switch electronically connected to the drive shaft and the batteries, the drive shaft actuated by the switch and the batteries, the illuminating device having two bulbs and electrically connected to the switch.
USD 436,819 discloses an electronic screwdriver, which is a designed for the casing of an electronic screwdriver which seems to be in the shape of a portable electronic drill. The ornamental design shows a lower handgrip arranged in the vertical direction and an upper cylindrical shaped head casing arranged in the longitudinal direction with what seems to be a screw driver bit adjustable holder mechanism at the head of the casing.
U.S. Pat. No. 5,784,934 discloses a ratchet wrench with pivotal head. The ratchet wrench has a handle for gripping and a head having a ratchet mechanism including a drive shaft capable of powered rotation about its axis. The head and handle have openings in registration with one another and a pin is received through the openings interconnecting the handle and head, which permits pivoting movement of the handle and head relative to one another about a longitudinal axis of the pin to any multiplicity of selected angular orientations. The ratchet wrench includes a transmission constructed to transmit power from the motor to the ratchet mechanism through the pin interconnection of the handle and head.
U.S. Pat. No. 5,251,706 discloses a ratchet drive tool with manual and non-manual power actuation where the power source is supplied by a battery, or an electrical or pneumatic supply. A drive shaft extends coaxially from the housing which contains speed reducing/power amplifying structures and the drive shaft is connected to the head of the device through a pivot joint assembly.
U.S. Pat. No. 6,293,172 discloses a telescopic pocket door angle drill which has a right angle driver with a telescopic handle portion which can be extended to reach into confined spaces. The right angle driver has a casing and an internal gear assembly for translating rotary motion from horizontal drive to a vertical drive.
U.S. Pat. No. 4,970,918 discloses an adjustable tool for manipulating a fastening device such as a bolt or screw. The tool has a handle which is rotatable about a shaft, the shaft being inserted through the handle. A housing pivots about one end of the handle and has an end which can be rotated to manipulate a fastening device at angles of 0 degrees, 90 degrees, and 270 degrees from the drive shaft.